a. Forcing the cutter bar of a coal cutter into or under the coal. Also
called sumping cut.
b. A small square shaft, generally made in the airheadings when crossing
faults, etc., or made to prove the thickness of coal, etc.
An angle iron about 8 ft (2.4 m) long with flanges about 4 in (10 cm)
high, weighing about 75 lb (34 kg). Its function is to guide the cutter
bar on an electric coal-cutting machine. Fay
See:sump
See:jibbing-in
In metal mining, a person who installs sets of timbers to support the
walls of a shaft, working with the shaft sinking crew and installing the
timbers as the work advances. DOT
The shaft in a mine at the bottom of which is the sump.
Standard, 2
A blast made in a shaft that is being sunk, to make a collecting place for
water. Standard, 2
A winze sunk in the bottom of the lowest level, to explore the lode below
and ascertain whether the sinking of the main shaft is advisable.
Standard, 2
a. A sublithographic limestone or mudstone at the top of the White Lias,
the upper surface of which bears polygonal cracks attributed to sun
drying.
b. Alternatively a corruption of "sound" bed because, when dry, the rock
rings when broken with a hammer. CF:guinea bed; ring stone.
The south side of a vein. Arkell
See:mud crack
A calcareous deposit formed inside pipes carrying waste water from
collieries. It is composed of alternating dark and light bands
corresponding to the day and night shifts and a broader light band
corresponding to Sunday. Arkell
In electrical prospecting, an inductive method in which the current flows
through an insulated copper cable connected to a source of alternating
current and run along the surface in a rectangle 1 mile by 1/2 mile (1.6
km by 0.8 km) in dimensions. A series of transverse profiles are laid out
perpendicular to and crossing the cable, and the magnetic part of the
electromagnetic field is measured at discrete points along the profiles by
special search coils consisting of several hundred turns of wire. The
magnitude and direction of the induced field observed by the coils can be
related to the inductive effect of the subsurface material directly below.
Dobrin
a. A monoclinic mineral, Pb10 (SO4 )Cl2 O8 ;
forms plumose aggregates of adamantine crystals having one perfect
cleavage; at Laangban, Sweden.
b. A name proposed for a hypothetical amphibole end-member composition,
but never accepted by the IMA nor widely used by mineralogists.
See:andorite
The central gear in a planetary set. Nichols, 1
Drilled or excavated downward. Long
See:dig-down pit
A shaft that is driven from the top downward (vertical or inclined).
Fraenkel
See:fire opal
A name of a soft grade of paraffin wax with a low melting point. It can be
burned in an ordinary miners' lamp with a nail (usually copper) in the
wick and gives little smoke. Also called miners' sunshine.